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Biomedical subjects

M Ohashi

Publications and source records attributed to M Ohashi.

At least 127 records · Page 7Linked to original sources
PubMed1997

[A trial of laparoscopic assisted radical nephrectomy].

BACKGROUND: We tried a new procedure of gas-less laparoscopy assisted radical nephrectomy. METHODS: Prior to insertion of laparoscope, pararectal incision approximately 7 cm in length was made to enter into the intraabdominal cavity. A 12 mm trocar was placed just below the umbilicus and a flexible electroscope was inserted through it. A 10 cm size disposable fan for lifting up the abdominal wall was indwelled through the under space of trocar port. After appropriately lifting up the abdominal wall, a 10 mm trocar for working channel was placed at mid-axillar line. Under laparoscopic and trans-laparotomic views, radical nephrectomy was performed using the combined technique of laparoscopic and open surgery. RESULTS: Seven patients have been successfully treated with this procedure. The mean operating time of this procedure was significantly shorter than that of totally laparoscopic nephrectomy. The recovery time from the operation was as short as usual laparoscopic nephrectomy. CONCLUSION: We thought that this procedure could open a new scope of laparoscopic surgery.

Adult↗
PubMed1997

Elevated L-kynurenine level and its normalization by prednisolone in a patient with eosinophilia-myalgia syndrome.

We report a L-tryptophan-induced case of eosinophilia-myalgia syndrome in a Japanese woman and describe the time course of changes in tryptophan metabolism observed during steroid therapy. She had taken 1.0 g of the implicated L-tryptophan daily. When admitted due to painful swelling of her extremities, eosinophil count was 22.3 x 10(9)/L. Before prednisolone treatment, her serum L-kynurenine level was 10.2 mumol/L, a level about three-fold higher than the normal value, while serum tryptophan level was abnormally low (23.1 mumol/L). On the 14th day of prednisolone treatment (40 mg daily), L-kynurenine was declined to 8.1 mumol/L and, concomitantly, L-tryptophan level increased to the normal range (51.0 mumol/L). Subsequently, on the 42nd day of therapy, serum L-kynurenine was normalized. In contrast, serum serotonin level was unchanged throughout the course of this therapy. Prednisolone dramatically reduced the elevated serum L-kynurenine with a reciprocal increase in serum L-tryptophan indicates that abnormal tryptophan metabolism, may play a role in the pathogenesis of eosinophilia myalgia syndrome, and that the observed effect of steroid treatment was due to suppression of elevated activity of indoleamine 2, 3-dioxygenase, a first rate-limiting enzyme of the kynurenine pathway.

Anti-Inflammatory Agents↗
PubMed1996

Age-associated changes in the template-reading fidelity of DNA polymerase alpha from regenerating rat liver.

DNA polymerases (deoxynucleosidetriphosphate: DNA deoxynucleotidyltransferase EC 2.7.7.7.) were extracted from regenerating livers from young and aged rats. DNA polymerase alpha was separated and partially purified by DEAE-cellulose column chromatography, polyethyleneglycol precipitation, and phosphocellulose column chromatography, and fidelity levels were then monitored with the synthetic template-primer poly (dG-dC). The fidelity level of the DNA polymerase from regenerating liver a 4-month-old rat was very high, while that of the DNA polymerase from a 24-month-old rat was significantly decreased. To confirm this result, DNA was synthesized on poly (dG-dC) in a reaction mixture containing [32P]dTTP, and the synthetic polynucleotide was purified and digested with HhaI restriction endonuclease. After hydrolysis, the oligonucleotides were developed by two dimensional thin layer chromatography on PEI cellulose plates. Spots containing [32P]dTMP were observed when DNA polymerase from a 24 month-old rat was used, but none was found in polynucleotides synthesized using DNA polymerase from a 4 month-old rat. Nearest neighbor analysis suggested that dG-dT and dC-dT pairs were constructed by mis-incorporation due to DNA polymerase alpha.

Aging↗
PubMed1996

Chemical nature of the light emitter of the Aequorea green fluorescent protein.

The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda max = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser65-Tyr66-Gly67-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced. To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore. The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore. Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission.

Amino Acid Sequence↗
PubMed1996

Studies on selectin blockers. 2. Novel selectin blocker as potential therapeutics for inflammatory disorders.

As a part of our studies of selectin blockers, we prepared 1-(2-tetradecylhexadecyl)-3'-O-sulfo Le(X) 1 and 1-(2-tetradecylhexadecyl) sLe(X) 2 and examined their inhibitory activities against natural ligand (sLe(X)) binding to E-, P-, and L-selectins. Compounds 1 and 2 were 2 times more potent than the sLe(X) tetrasaccharide toward E-selectin binding and up to 4 times more potent than sLe(X) toward P- and L-selectin binding. Interestingly, compound 1 provided dose-dependent protective effects against an immunoglobulin E-mediated skin reaction in mouse ears. This protective effect was associated with diminished tissue accumulation of neutrophils in the ear (as assessed by myeloperoxidase). These findings indicate that the modification of sLe(X) or 3'-O-sulfo Le(X) with a "branched anchor", a 2-tetradecylhexadecyl group, is useful in the design of a more potent selectin blocker, which has broad inhibitory activities toward all selectins.

Animals↗
PubMed1996

The structural origin of the color differences in the bioluminescence of firefly luciferase.

Six chimeric mutants between Hotaria parvula (lambda max = 568 nm) and Pyrocoelia miyako (lambda max = 550 nm) luciferases were reconstructed to determine the structural origin of the color differences in firefly luciferase. Based on light-emitting color, five chimeric luciferases could be divided into two groups: the three green-emitting mutants, classified as P. miyako luciferase, and the two yellow-emitting mutants, classified as H. parvula luciferase. Their common fragments between Val-209 and Ala-318 within each group contain the active site for the color differences.

Amino Acid Sequence↗
PubMed1996

Serial transplantation in SCID mice of an epidermodysplasia verruciformis-associated squamous cell carcinoma without alteration of its histological and virological features.

An epidermodysplasia verruciformis-associated squamous cell carcinoma was xenografted to a SCID mouse, and the resultant tumor was transplanted through mice for 10 generations. Histological and virological features, with replication of about a thousand copies of the papillomavirus DNA, were the same in both the original carcinoma and the transplanted tumors.

Animals↗
PubMed1996

A charged segment mainly composed of basic amino acids forms an autoepitope of CENP-A.

Autoantibodies against centromere proteins are commonly found in the serum of patients with scleroderma and other systemic autoimmune diseases. The reactivity of anticentromere autoantibodies (ACA) from 78 patients was investigated by ELISA using two kinds of a 15-amino-acid peptide corresponding to the N- and C-termini of CENP-A, one of the target molecules of ACA. The N-terminal peptide (residues 3-17) was recognized by 85% of ACA, while the C- terminal peptide (residues 126-140) was not. The ELISA result for the N-terminal peptide correlated with the immunoreactivity of CENP-A observed in immunoblotting. Moreover, the binding between autoantibodies and CENP-A was inhibited by the N-terminal peptide in 98.5% of anti-CENP-A- positive sera in immunoblotting. The sequence of peptide, PRRRSRKPEAPRRRS, is highly charged and has two repeats of PRRRS. These results indicate that the N-terminal-charged region forms a major epitope of CENP-A. This area may be involved in the induction of specific autoantibodies against centromere in autoimmune patients.

Amino Acid Sequence↗
PubMed1996

E7 proteins of four groups of human papillomaviruses, irrespective of their tissue tropism or cancer association, possess the ability to transactivate transcriptional promoters E2F site dependently.

In an experimental system in which an expression vector including the E7 gene of a given human papillomavirus (HPV), together with a luciferase reporter plasmid including the adenovirus E2 (Ad E2) promoter, was transiently transfected into cultured mouse NIH3T3 fibroblastic cells, we obtained the signal indicating that E7 proteins of HPV type 5, 12, 14, 20, 21, 25, and 47, which are associated with epidermodysplasia verruciformis (EV), can transactivate the Ad E2 promoter, as previously reported for E7 proteins of other HPVs. Because the underlying mechanism of the transactivation had not been analyzed, except for transactivation by E7 gene of cervical cancer-associated HPV-16, we compared the E7 genes of representatives of three other groups of HPVs (HPV-1, -11, and -47) with that of HPV-16 with regard to their transactivating activity toward artificially constructed promoters. The experiment with a shortened AdE2 promoter carrying only the E2F sites and TATA box provided evidence that all four E7 proteins can transactivate the shortened promoter and that this phenomenon is E2F site dependent. Further experiments with the reporter gene constructs carrying basal promoters or more complex forms with or without linked E2F sites, (a) confirmed previous finding by others that in cells producing no transactivator, the transcriptional level from promoters linked to E2F sites is rather repressed in comparison with the level of the corresponding promoters that are not linked to the E2F sites, and (b) demonstrated, for the first time, that in cells expected to produce the E7 protein of any one of the four HPVs, transcription from the promoter linked to the E2F sites was released from repression. In other words, the present results reveal that E7 proteins of any of the four HPVs can remove the E2F site-dependent repression, probably by modulating E2F complexes from repressing forms to activating ones.

Base Sequence↗
PubMed1996

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To determine predictors of stroke in patients undergoing first-time coronary bypass grafting, we prospectively collected data on 1631 consecutive patients. METHODS: Patients with a history of stroke and/or central nervous system symptoms (n = 134) and/or carotid bruits (n = 95) underwent carotid Doppler evaluation. Stenosis greater than 70% was considered significant. Patients with symptomatic disease or asymptomatic bilateral disease were referred for combined coronary bypass and carotid endarterectomy (n = 21). Patients with neurologic symptoms after the operation were assessed by a neurologist and underwent a computed tomographic scan. Events were classified as reversible transient ischemic attack, reversible ischemic neurologic deficit, or irreversible stroke. RESULTS: There were 19 strokes (1.2%) and 20 deaths (1.2%) in this series. In patients with carotid screening, risk of stroke increased with severity of carotid disease and ranged from 0% in patients without stenosis, to 3.2% (1/31) in those with greater than 70% stenosis, and to 27.3% (6/22) in those with carotid occlusion. By stepwise logistic regression analysis six variables were identified as risk factors for stroke. The most important predictor was carotid occlusion with or without contralateral stenosis (odds ratio = 28, 95% confidence interval (8,105). In this group, four of five strokes occurred on the occluded side. Other risk factors were presence of ascending aortic disease at the time of surgery (odds ratio = 12.8, confidence interval 3,48), perioperative myocardial infarction (odds ratio = 8.2, confidence interval 2,33), poor left ventricular function (odds ratio = 4.6, confidence interval 1,19), peripheral vascular disease (odds ratio = 3.2, confidence interval 1,9), and age > 60 years (odds ratio = 2.9, confidence interval 0.8,11). CONCLUSION: We conclude that risk factors for perioperative stroke in patients undergoing coronary artery bypass grafting are multiple. Carotid scanning in patients with neurologic symptoms or carotid bruits can identify patients at increased risk. Patients with carotid occlusion are at high risk for stroke on the occluded side.

Adult↗
PubMed1996

Vibration-induced finger flexion reflex and inhibitory effect of acupuncture on this reflex in cervical spinal cord injury patients.

The vibration-induced finger flexion reflex (VFR) and the inhibitory effect of acupuncture on this reflex were studied in five cervical spinal cord injury patients (C-SCIs). VFR, which is a tonic finger flexion reflex induced by vibratory stimulation on the finger tip, was induced before and after acupuncture was carried out on the same hand. A stainless steel needle was inserted to the Hoku point. As in healthy subjects, VFR was performed and it was significantly inhibited by acupuncture in the C-SCIs; mean maximum VFR was 204.2 +/- S.E. 68.6 g before and 119.8 +/- S.E. 42.2 g after acupuncture. The present results suggest that at least part of the reflex center for VFR is located in the spinal cord and that part of VFR inhibition by acupuncture may be mediated via the spinal cord.

Acupuncture Therapy↗
PubMed1996

Clinical features of anti-chromo antibodies associated with anti-centromere antibodies.

Anti-chromo antibodies (AChA) are autoantibodies accompanying anti-centromere antibodies (ACA). We determined the frequency and clinical significance of AChA in autoimmune rheumatic diseases. Serum samples from 252 patients with rheumatic diseases were examined by immuno-blotting with HeLa nuclear extract and with recombinant N-terminus of 25-kD chromo protein (p25). AChA were detected in 28 (36%) of 77 sera with ACA. AChA were found only in ACA-positive sera. Twenty-two (79%) of 28 recognized a recombinant N-terminal portion of p25, including the chromo domain which is conserved among species. AChA were related to leucopenia, thrombocytopenia, elevated erythrocyte sedimentation rate, and existence of Sjögren's syndrome (SS). In ACA-positive patients, AChA might be a serologic indicator of systemic sclerosis (SSc), having features of systemic lupus erythematosus and/or SS or diseases other than SSc.

Autoantibodies↗
PubMed1996

Analysis of K-ras gene mutation in hyperplastic duct cells of the pancreas without pancreatic disease.

BACKGROUND & AIMS: We and others have previously shown that the mutation of K-ras codon 12 was found in the majority of pancreatic adenocarcinomas. The mutation has also been identified in the pancreatic duct with mucous cell hyperplasia in association with chronic pancreatitis. Ductal hyperplasia is also frequently found in the pancreas free from pancreatic carcinoma or chronic pancreatitis. The aim of this study was to assess the incidence and types of mutations in hyperplastic foci in these cases. METHODS: The nucleotide sequence of the K-ras gene at codon 12 of the DNA extracted from microdissected hyperplastic epithelium of the pancreatic duct obtained at autopsy in patients without pancreatic adenocarcinoma or chronic pancreatitis was analyzed. RESULTS: Of 38 patients with 79 hyperplastic foci, 12 patients (with 19 hyperplastic foci) had mutations. None of the 16 normal ducts in 12 specimens had this mutation. The nucleotide sequence of the codon in 53% of ductal hyperplastic foci was TGT or AGT, both of which were not found in 30 cases of adenocarcinoma. CONCLUSIONS: These results suggest that the ras gene mutation occurs frequently in multifocal hyperplastic foci of pancreatic duct and that the mutations may not have direct relevance to the carcinogenesis of pancreatic cancer.

Adult↗